Helicopter



Feb. 25, 1930. c, u w cK T AL 3 {148,520

HELICOPTER Filed June 17, 1.929

Patented Feb. 25, 1960 1 UNITED. STATES PATENT OFFICE.

Amazon oncn. mmwrcx, ARTHUR FRANK IAGO, AND xnnnn'rn MELVILLE HUNTER,

or LONDON, ENGLAND HELICOPTER Application filed June 17, 1929, SerialNo. 371,478, and in Great' Britain May 11, 1928.

This invention is for improvements in or Like reference numeralsindicate like parts relating to helicopters and has particular ref- 1nthe several figures of the drawings.

erence to helicopters intended to be used as Referring to Figures 1 and2 a bodyportoys, tion or fuselage 1n the form of a cardboard Theinvention is concerned with helicoptube 11 has thln end caps 12 and 13of wood 55 ters of the type comprising in combination a glued to theends. of the tube. An alr-screw body-portion or fuselage, two alr-screwsof 14 Wlnch would be uppermost when the heliopposite hand spaced apartin the length of copter 1s 1n filght is mounted for rotatlon 1n thefuselage for rotation about the same axis the end cap. 12 and about thecentral throughand means for driving said air-screws in y X1 0f the tube11 The alr-screw 14 an o it di ti so i t d to. the COHIPllSGS' a woodenstrip 15 and blades 16 screws that each exerts a lifting effort on ofstiff paper, OBllUlOIChOI' the like. The th f l wooden str1p 15 of thealr-screw is clamped The present invention comprises a helicopat Itseentife In a metal Strap 17 WlllCll has 15 ter of the type describedwherein the air- Secured t0 ltashaft 18. I screws are so constructed orarranged (e. g. he Shaft 8 passes through a small hole 1n with respectto the construction and disposih illlng (1180 19 wh ch rests upon theend tion of their effective surfaces) that the airp 12 a retalnedbyunturned pr0 ect1ons screw which is uppermost in flight develops Whlchengage 1n holes in the end cap. A

20 a greater lifting effort than the other a ir- -s ap d W her 20 1sprovlded between screw for the purpose of obtaining stability h rap 17and the bearlng d sc. in flight, The lower air-screw 21 coI npr1s1ng awooden P f bl th i hi h ill b strip 22 and blades 23 sim lar to blade 16of uppermost in flight has a larger span than the ppe elfrew, 1Sprovlded at its 25 that of the other air-screw. Further, the centrewltha W I' ye 24 whlch engages 111 blades of the uppermost air-screw (or atleast a S10t end p 13 whlch slot 1s of such th i ff ti ti may b arrangedt d1111I1S 10I1S as to prevent rotat on of the alrbe substantiallyoutside the circumferential 1n the end @P- The l Shaft 18 f compass ofthe lower air-screw. Also the the tin-screw 14 13 formed 1135 W 1' ex-30 blades of the lowerair-screw maybe set at a P f as a hook 25 i a'stnpof rubber 26 greater angle of incidence than the blades of t gi i {fiandhthe eye of the upper air screw e air-screw pre era y 1n sue a manneras to providea luralit of turns. It will thus In a pleferrid 9 theblades of the be clear that wlien theZubber stri is twisted screws areso mcllned to the fuselage that b turning the aipscrew 14 t 35considering the helicopter in flight the blades y b W0 will extendoutwardly and upwardly from gi l gfig fi W111 be rotated m PP thefuselage- I The blades 16 and 23 of the air-screws are In theaccompanymg drawmgs there Is so arranged as to be of opposite hand thatis lustl'ated y W y of pl Several f fi to say, when they are rotated inthe approtions of P accordmg to thls-lnvenpriate opposite directionsthey will both extion. ert a lifting efl'ort. In the drawings The bladesof both the air-screws are in- Figure 1 is a perspective View of the heclined to the tube 11 in such a mannerthat copter, considering thehelicopter in flight with the Figure 2 is a detail View s w g theair-screw 14 uppermost the blades will extend mounting of the air-screwson the fuselage, t rdly and upwardly from the fuselage and I tube 11.The air-screw 14 has a larger span Figures 3 and 4 are elevations ofmodified than the air-screw 21 and the blades 16 of the constructions ofthe helicopter. air-screw 14; are arranged substantially outside thecompass of the blades 23 of the airscrew 21. The angle of incidence ofthe blades 16 is also substantially less than the angle of incidence ofthe blades 23. Further, the pitch of the blades, and their relativeareas, may be so arranged that considerin the helicopter insustentation, the axial flow t rough the disc swept by the lower bladesmay have the same velocity as the flow through the annulus swept by theupper blades.

When, after energizing the helicopter by twisting up the rubber strip,the helicopter is released the two air-screws will be rotated inopposite directions by the unwinding of the strip. The air-screws beingof opposite hand and the rotation being in a proper direction both willthrust a column of air downwards and the helicopter will rise. It willbe clear that the upper and lower air-screws of the helicopter may beregarded as the equivalent of a single airscrew, the uppermost blades ofthe helicopter being that part of the blades of the equivalent airscrewlying outside a given circle described with its axis as centre, thelower air-screw of the helicopter being the equivalent of the partwithin such circle but with the pitch of the blades reversed e. g. (ofopposite hand).

The radius of the said circle, for the purpose of determining the bladeform may be such that the areas of the upper blades may be greater orless than, or equal to, the areas of the lower blades; thus the bladesmay be proportioned so that they may rotate in opposite directions atequal speed, or at different speeds with relation to each other. Apreferred arrangement is one in which the lower blades are slightly lessin area than the upper ones and rotate faster, e. g. the tip speeds maybe equal. It will be clear that the uppermost airscrew having the lesserangle of incidence and the greater span will be more efficient as alifting airscrew and thus as the reater part of the lifting effort isdeveloped y this airscrew the helicopter will be stable in flight. Thelower airscrew 21 isretained in position by the tension in the rubberstrip which in effect provides a resilient connection for the lowerairscrew and the tube 11 and thus largely obviates possible damage ofthe lower gir-ficrew when the helicopter falls after a ig t.

It will be understood in the construction just described that thefuselage tube 11 will rotate with the air-screw 21. Alternatively, theair-screw 21 may be rotatably mounted in the end cap 13 by providing itwith a shaft and bearing similar to that provided for the air-screw 14.I 1

Instead of connecting the lower air-screw to the end cap 13 it may berigidly secured. to the tube 11 at some distance from that end of thetube which will be lowermost in flight as shown in Figure 3.Alternatively, the airscrew 14 which is-uppermost in flight may berigidly secured to the tube 11 at some distance from the top of the tubeand the lower airscrew 21 will then be rotatabl mounted in the lower endcap 13 in a simi ar manner to the mounting of the air-screw 14 in Figure2. In both the constructions shown in Figures 3 and 4, the rubber strip26 is looped on to the hook formation of the shaft of the rotatableair-screw and on to a suitable hook secured to the tube 11 at theopposite end thereof.

It will be understood that modifications may be made in the constructionof the helicopters hereinbefore described without departing from theinvention.

We claim 1. A toy helicopter comprising a fuselage, two air-screws ofopposite hand disposed at spaced points on the fuselage for rotationabout the same axis, and means for driving said air-screws in oppositedirections, the airscrew at the leading end of the helicopter inlaunching being larger in span than the following air-screw, whereby agreater lifting effort will be developed by the leading airscrew for thepurpose of obtaining stability.

2. A toy helicopter comprising a fuselage, two air-screws of oppositehand disposed at spaced points on the fuselage for rotation about thesame axis, and means for driving said air-screws in opposite directions,the effective portions of the air-screw at the leading end of thehelicopter in launching bein substantially outside the circumferentiacompass of the effective portions of the other air-screw, whereby theleadingair-screw will develop the greater lifting effort for the purposeof obtalning stability.

In testimony whereof we have signed our names to this specification.

ARTHUR CECIL NUN WICK. ARTHUR FRANK IAGO. KENNETH MELVILLE HUNTER.

